soda blasting old paint

[elmo]

there is a place here in New Zealand that specialises in paint stripping that has a tank that i have seen them dip a early 50's cadillac in to .it is acid dipped first then redipped twice more in other tanks to neutralise the acid and clean it before etch priming.

[Mopar Al]

Iv'e been sand blasting for years.  Refridgerators, bicycles, metal cabinets, among others, and of course cars.     There are many different types of medium.  walnut shells for engines are great. I have never had a warped body panel from sand.  I have seen them warp from to much pressure when hand sanding with to small of a block.   I did alot of research before buying my pressure blaster,  and compressor, and they have worked well for me.       I can't imagine putting a complete chassis into a chemical tank.               
                                                                                                      Mopar Al

[POC-Admin]

Soda blasted surface just needs a good clean with something like Metal-Prep - mild acid wash before thinner rub-down and primer.

Walnut Shells are another good medium to blast sheet metal with.

[Wm Steed]

I took  the body on my '39 Plym completely apart so I could have it chemicaly stripped in a tank. The metal came out looking like it was brand new with no distortion. Of course the areas that were badly rusted out looked like cheese cloth.  The majority of GOOD body men I know will not work on metal that has been sand blasted, reason being that sand blasting makes the metal brittle because the sand tends to "peen" the steel making it brittle. Glass beads are not as bad as sand, but glass will also upset the metal.

Soda blasting has become the medium of choice for paint  removal on light guage body metal, soda is so gential it will hardly etch glass. I think after all is said and done having body parts dipped is the best method of removing paint and rust, however, be prepared for a shock when you get lmetal back that looks like cheese cloth....Bill

[FourDoor]

Soda blasting is used exclusively now in Canada on sheet metal. As far as I know no one uses sand except on chassis parts or forgings. I had some soda done and then the metal was covered with 2 part high build up epoxy primer.     

[Tony D.]

My stripper uses crushed garnet from North Carolina.  The material leaves a etched glass-like surface and I prime it with red oxide primer.   This method does not warp the metal, I did have that experiance in the 80s when a monument maker sandblasted my Ramcharger's hood and tailgate.  The hood's skin depressed about a 1/16" where it wasn't supported by the inner frame.  I also sandblast some parts at home, but 15 cfm at 90 psi is not enough to heat steel.

[elmo]

back again i seem to have done something i shouldn't have i cut myself off in mid stream,to continue.  is the only way to go ,unless you can find some one with a big enough chemical stripping tank that will take your whole car. the draw back to that is you have to completely dismantle the car. after getting it to bare metal avoid touching it with bare hands as every where you touch could/will blister the paint later,use rubber gloves. After treating the metal with a metal pretreatment (i use dioxadine) it should be etch primed prefebly using a two pack etch primer.  Rex

[elmo]

John   Ihave been a car painter for most of my working life (now retired). I have never heard of soda blasting before, but then i live at the bottom of the world. Dennisks is right sandblasting can distort the metal and deffinately pits it makeing  more work and expense to get a smooth finish. paint stripper or glass bead blasting and a bit of old fashioned hand sanding

[DENNISKS]

John

I am in the middle of repainting my car. I had never heard of soda blasting. I took paint stripper to my car first and then sanded it with a DA air sander. The parts that I needed blasted I took to a professional in Fort Wayne, IN. He did however tellme not to sand blast the old parts because sand blasting will disfigure the metal. I believe he uses steel shot. His reasoning was sand causes the metal to get too hot. Thus disfiguring it.  My parts came out great and the cost was not bad. By using the paint stripper first he said I would save a lot of time and cost. I had my fenders blasted and a few small parts.

Here is my car as of today. Boy do I have a lot of work to do!

[30 Ply 30U]

After the soda blast, a light hand sand, then you need to start back at etch primer on bare steel.

[John Hendricks]

Any one had any experience with soda blasting old paint off of sheet metal prior to repainting?  Any special prep to the blasted metal?